But it was Wednesday that produced what the blog for The Last Word With Lawrence O'Donnell touted as the "week's must-see" moment: Mr. O'Donnell chastising an Iowa congressman over comments by an Iowa voter Fox talked to in the aftermath of the Obama confrontation. The voter had alluded to Mr. Obama's "Muslim" faith--a bit of misinformation for which Mr. O'Donnell hoped Rep. Steve King, a Republican, might take some "responsibility," since he had not used the recent campaign season to correct the record on the issue. When the congressman declined, Mr. O'Donnell enhanced his interrogation technique:

Mr. O'Donnell: Are you a Christian?

Mr. King: Yes, sir.

Mr. O'Donnell: Should I take you at your word or should I maybe suspect that you're a Muslim? Do you have a Christian ID you can show me and prove that you're a Christian?

Mr. King: I think I was going to ask you to not judge me as I'm not judging President Obama--

Mr. O'Donnell: Do you have a Christian ID?

Mr. King: No one has a Christian ID--

Mr. O'Donnell: Catholics get birth--get baptism certificates! There are some religions that issue certificates of certain kinds. Do you have any?

Mr. King: I don't think so. I was baptized--

Mr. O'Donnell: [yelling] How do we know you're not a Muslim? How do you know someone is not a Muslim and is a Christian? 

On it went, Mr. O'Donnell repeatedly interrupting the congressman he had invited on his program to discuss the outrage of Mr. O'Reilly's repeated interruption of the non-Muslim commander in chief. There were other ironies, but most viewers attuned to register them were preoccupied with the overthrow of the Egyptian dictator transpiring on numerous other channels.

Since Mr. O'Donnell replaced Keith Olbermann in the coveted 8 p.m. time slot last month, he has specialized in the sort of news (Sarah Palin, Michele Bachman, the Darth Vader kid from the Super Bowl commercials) preferred by people who can't be bothered to follow the news. The formula has on some nights proven such a disaster that viewers have flocked to Parker Spitzer on CNN, suggesting they might also be coaxed to Al Gore's fledgling Current TV come May, when Mr. Olbermann is expected to debut a new 8 p.m. show on the network.

Until then, watchers of MSNBC are stuck with Mr. O'Donnell, a vigorously vacuous character whose insipidity of subject matter is matched only by his sanctimony. Night after night, his bizarre riffs breed sound bites that migrate to commercial teasers reinforcing the nascent Lawrence O'Donnell brand. Currently in rotation is a bit about Gabrielle Giffords' shooting from last month in which, nostrils aflare, he scolds a Republican congressman for not supporting (mostly theoretical) legislation that would ban the sale of guns with clips capable of holding more than 10 bullets. What of the lives such a law might have saved in Tucson? Representative Trent Franks, of Arizona, a good sport, likens "focusing on the clip" to "sayin' we're gonna combat drunk driving by limiting the size of fuel tanks."

"I blame the individual," thunders Mr. O'Donnell, "for the first 10 bullets. I blame the law for the next 21 bullets!"

No guest is too benign or inconsequential to serve as Joe McCarthy to Mr. O'Donnell's eager inner Edward R. Murrow, and, more important, no argument is too sound if Mr. O'Donnell is in the mood for a bout of self-righteous condemnation. If this sounds not too different from Mr. Olbermann's blowhard fare, try to imagine Mr. Olbermann being impersonated by David Hyde Pierce's character Niles from Frasier--and being contractually obliged to choose his targets on the basis of a strict 40-60, blue state-red state quota system. (For reasons as yet unclear, progressives too are a regular target of Mr. O'Donnell's bile barrages.) Innocent sentences--"Gabby Giffords spoke for the first time since sustaining a gunshot wound to the head last month; [sneering] she asked for toast!" "Sarah Palin has not exactly mastered the Reagan optimism thing yet"--issue from his mouth with a weird coating of contempt.

For all of Mr. O'Donnell's bluster about baptism certificates and identification cards, details of his own biography are murky. A recent Women's Wear Daily profile puzzled over the disparity in reports of his age; most sources list it as 59, but he graduated from Harvard in 1976, which, if true, would have made him nearly 25 years old at the time. That detail would be less troublesome had he not also reportedly eschewed all drugs and alcohol in youth. The few stories that have been written about Mr. O'Donnell over the years invariably mention his affiliation with Harvard's venerable humor magazine, The Lampoon, where he reportedly met (among others) the future Saturday Night Live writer and television executive John Bowman, but Mr. Bowman later recalled that Mr. O'Donnell had not actually done anything for the magazine, and that the staff had merely considered him "cool." (Granted, Mr. Bowman, who didn't graduate until 1980, might not have known what he was talking about.)

That Mr. O'Donnell somehow emerged from an Irish Catholic upbringing in working-class Boston calling himself "Lawrence" in the age of Larry Bird dovetails with his other known affectations: His earliest recorded flirtation with punditry is a 1985 New York Times op-ed on the superiority of designer Italian suits to the Brooks Brothers numbers he wore before an episode of Miami Vice inspired him to tour Barneys. (More recently WWD touched off a predictable memelet by noting the provenance of his socks as something called Seize sur Vingt.) His life took a fateful turn around the time of his sprucing up, when he took a sublet in the apartment of Maura Moynihan, whose cartoonish dilettantishness--she was a performance artist in the midst of a conversion to Tibetan Buddhism--no doubt cast her roommate in a favorable light when she introduced him to her late and lionized father, Daniel Patrick Moynihan, then senior senator from New York. By all accounts, he was smitten by his pompous pupil, and a reluctant politico-cum-pundit career was launched.

For the first five years of the 1990s, Mr. O'Donnell was Mr. Moynihan's most trusted adviser, and he has been trading on the collected legislative failures of that era ever since. Having entered a minimalist and misanthropic phase of his career, Mr. Moynihan openly distrusted Hillary Clinton's health care agenda, and together with Mr. O'Donnell he used his clout as chairman of the finance committee to water down the proposal, eventually destroying it. (Believing the "real" crisis was welfare, not health care, he tirelessly advocated welfare reform--until the Republicans took control of the process in 1994, after which Mr. O'Donnell counseled him to vote against it.) Most ignominiously, just before the 1994 election, Mr. Moynihan appointed Michael Boskin to chair the commission that eventually oversaw the re-jiggering of the consumer price index in such a way that served only to shortchange the poor, sick and elderly by permanently underreporting inflation.

Mr. O'Donnell resigned to embark upon full-time punditry in 1995, after (although not officially because of) a story in The Hill reporting on financial disclosure forms showed that he had made 30 separate round-trip New York-D.C. flights at taxpayer expense during the six most frenetic months of the health care debate. Pious, anachronistic Democrats with proven track records of antagonizing the Clintons were much in demand during the second half of the decade; and then Mr. O'Donnell got a job on The West Wing.

For its producers and fans, The West Wing offered refuge from America's vicious atmosphere of permanent culture war, for at least an hour a week. Its bleeding hearts did not double as pumps for reckless libidos; it did not cynically exploit tragedies to harden hates. But terror attacks and rogue states, hate crimes and secret sexual proclivities set against a backdrop of earnest debates about affirmative action and school vouchers--culture war detritus, generally--was still the stuff of the plot summaries (economics, the historical distinction between the parties, was left out), and The West Wing, like the punditocracy in which Mr. O'Donnell plied his talents on nonfiction occasions, was an apologetic byproduct of the Clinton administration.

MSNBC, by contrast, saw its flourishing during the Bush administration. Starting with Keith Olbermann, who founded Countdown in 2003 after a broadcasting career spent mostly at ESPN, the network assembled a lineup of prime-time personalities largely from far outside the Beltway, most of whom had done no time in the political media and barely identified as "liberals," much less "Democrats." The network rode the same tide as the rising political blogs and online activist communities, and it was the repeated traumas of the Bush administration, and none of the typical D.C. "horse race" romanticism that characterized the West Wing crowd, that galvanized and defined it.

Erstwhile Hill hacks like Mr. O'Donnell and Chris Matthews were still needed, of course, to report on palace intrigue and teach the true believers how the system actually works. In 2005, for example, Mr. O'Donnell somehow got wind of the fact that Karl Rove had been subpoenaed by a grand jury for being a source of the Plamegate leaks; three paragraphs about the scoop he sent to his friend Arianna Huffington ended up being the Huffington Post's first big traffic jolt. At the same time, Mr. O'Donnell was probably more immersed in the West Wing world--where the libertarian Republican presidential candidate (played by Alan Alda) he'd concocted was fast becoming a writer's room favorite to "win" the show's upcoming "election"--than the real one, in which the bloody failure of basic essential government services and functions was becoming a sort of Bush administration trademark. A few months later, he recalled a writer's room argument with a female cast member over economics to a columnist at the conservative Pittsburgh Tribune-Review:

"I tried to make it easy for her. I said, 'Here's my position: My position is, slavery is better than death. Employment is better than slavery. Exploitative wages are better than nothing. And that a fair wage and justice is the ideal.' And she can't accept that. She can't accept any sentence that isn't about the fair wage and the ideal. Literally and truly. She's a very, very smart woman. She couldn't process what I was talking about. She couldn't process that one penny is better than zero. There are children in the world who would be lucky--lucky--to be employed 12 hours a day in exploitative child labor situations where they are making 10 cents a day. Unfortunately, I think respect for the market seems to be something that I have not seen anyone derive outside education."

Such sentiments (along with his legislative record undermining the Clinton universal health care plan) notwithstanding, Mr. O'Donnell bafflingly insists on using the term "socialist" whenever asked to identify his place on the ideological spectrum. He spent most of the election season skewering the progressive faction of the Democratic party for undermining the Obama agenda, and when bloggers like Salon's Glenn Greenwald took note of it, he mocked them. "Glenn, unlike you, I am not a progressive," went a milder-than-usual dressing-down. "I am not a liberal who is so afraid of the word that I had to change my name to progressive. Liberals amuse me. I am a socialist. I live to the extreme left, the extreme left of you mere liberals, O.K.?"

Perhaps because of this supposed kinship, though, Mr. O'Donnell reserves his most bizarre and strident attacks for bona fide leftists, like former Florida congressman Alan Grayson, who appeared on The Last Word in December to voice opposition to the Obama administration's compromise extending the Bush tax cuts another two years.

"Congressman!" the host demanded, "if you were to succeed at this, and kill this bill, do you know which bracket would actually get the biggest tax increase?

"However," he went on, "I know this about my country. Liberals are 20 percent of the electorate. Conservatives are 41 percent of the electorate. ... The only way, the only way you have a Chairman Barney Frank, there's only one way--that's by electing Blue Dogs."

"Yes," Mr. Grayson replied. "The people who have dividend income--"

"Wrong!" Mr. O'Donnell launched into another dressing-down for which he would later apologize on Twitter. "Congressman Grayson, it's the bottom tax bracket, not the top tax bracket, the bottom tax bracket would go from 10 percent to 15 percent. That is a 50 percent increase in the bottom tax bracket. [yelling] You are wrong, sir! You are wrong! In dollar terms the money is at the top end, but in percentage terms the money is at the bottom--"

As it happened, Mr. O'Donnell was wrong, on his terms as well as those of any sane debate, but Mr. Grayson did not seem terribly offended, even when Mr. O'Donnell excoriated him to "be an adult about this," at which point he laughed a little, threw up his hands and rolled his eyes. He made a final appeal to his host. "Come on--this is supposed to be the intelligent network!"

            editorial@observer.com